Okay, IIRC, in 1999, the complete motor/gear assembly and the controller was changed. As part of that change, the magnetic door switch changed from a NC to NO switch. When the door is closed, the switch applies ground to the brown wire and that should close the door.
As I understand it, another part of the change included using an entirely new controller. Prior to 1999 the controllers were color coded, after 1999 they all became black.
What color controller do you have?
The fact that your steps are doing nothing at all suggests either a bad motor or bad controler. If you simply had the wrong switch, the steps would extend when you closed the door and retract when you open the door.
Where are you testing the brown wire for voltage?
I'm off to bed and will check for your answers tomo=ow.